Electronic imaging or scanning systems are commonly used to transform an image on an image-bearing surface from one form, such as a paper original, to an electronic form, such as a digital or analog signal. Once an image is converted to an electronic form, many uses of that signal become possible, including, without limitation, the reproduction of the image onto a piece of paper, the projection of the image onto a video display terminal, the transmission of the image to a remote location, and the further processing of that image, such as by a computer, an optical pattern recognition device, or the like.
Electronic imaging systems typically include an array of photosensitive elements, such as photosensors, and a light source operatively disposed to provide illumination of the surface being scanned. In those instances where a linear array of photosensitive elements is employed, it is necessary that either the image on that surface is moved in a direction perpendicular to the longitudinal axis of the linear array, or the linear array of photosensitive elements is moved in a direction perpendicular to the longitudinal axis of that surface. Alternatively, in those instances where a two dimensional array of photosensitive elements is employed, the entirety of the document may be scanned without the need for relative motion therebetween. Regardless of whether linear or two dimensional arrays are employed, the light reflected from the image-bearing surface varies depending upon the image on any small area portion of the surface being scanned, i.e., a darker portion of the surface will cause the photosensitive elements to receive less reflected light, while a brighter portion of the surface will cause the photosensitive elements to receive more reflected light. Since the photosensitive elements effect a detectable change in the electrical conductivity thereof in response to the receipt of differing amounts of incident radiation, the change in conductivity can be detected and relayed in the form of electrical signals.
It will be appreciated that electronic image scanning systems are of great commercial utility insofar as they permit the conversion of human readable data into electronic format, which format is compatible with various electronic processing, transmission and storage operations. Accordingly, electronic image scanners have gained acceptance in such diverse fields as publishing, finance, engineering, telecommunications and the graphic arts. Since electronic image scanners are essentially the "eyes" of data processing systems, their ubiquity should be as great as that of the desk-top computer terminal; however, such is not the case at the present point in time owing in part, to the expense, size and limited scanning capacity of heretofore available scanners.
The assignee of the subject invention has already developed large area electronic image scanners which are specifically adapted to reproducibly scan a pattern of information on a drafting table or a marker board and produce a digital signal corresponding thereto. Such large area scanners are disclosed in commonly assigned U.S. patent application Ser. No. 885,907 filed July 15, 1986 and entitled "Photosensitive Line Imager Utilizing A Movable Scanning Arm", the disclosure of which is incorporated herein by reference. Applicants are also aware of various other commercially available image scanners; however, all of such scanners are relatively large, complex and expensive systems. Therefore, the need remains for a small electronic image scanner, suitable for portable use. Such a scanner should be relatively simple to operate and fairly inexpensive so as to be readily available as an adjunct to personal computing systems and the like. Furthermore, it is highly desirable that any such electrical image scanner be capable of scanning irregularly shaped or oversized documents such as bound material, newspapers, magazines, plywood, textiles and the like.
The aforementioned industrial needs are fulfilled by the portable digitizing wand disclosed herein. More specifically, the instant invention provides for a compact, low cost electrical image scanner capable of providing a digital signal corresponding to information upon a wide variety of substrates including, single printed pages, bound materials, oversized documents and drawings or the surface condition present on woods, metals, plastics and textiles.
The scanner of the present invention comprises a portable digitizing wand, said wand equipped with an array of photosensitive elements housed internally thereof. Manual scanning of the variety of documents, or other information-bearing surfaces, may be readily accomplished by merely passing the wand across the information-bearing surface so as to bring the photosensitive array in close proximity to the image-bearing surface. Relative motion between the document to be scanned and the wand is achieved by moving the wand past the stationary document. In this manner, the image scanner of the instant invention is adapted for the automatic scanning of image-bearing documents in a manner akin to the more conventional scanners referred to hereinabove.
It may thus be seen that the present invention discloses a unique electronic image scanner which is of relatively small size so as to provide for the use thereof in libraries, public transportation vehicles or other work areas in which access to an electrostatic copying machine is restricted. In its most simplistic form, the image scanner of the instant invention includes a portable digitizing wand which may be used in a "proximity focusing" manner so as to manually scan bound or odd-size documents.
These and other features and advantages of the present invention will be apparent from the drawings, the brief description of the drawings and the detailed description of the drawings which follow.